Light-modulated vertical heterojunction phototransistors with distinct logical photocurrents

Jiayue Han; Meiyu He; Ming Yang; Qi Han; Fang Wang; Fang Zhong; Mengjian Xu; Qing Li; He Zhu; Chongxin Shan; Weida Hu; Xiaoqing Chen; Xinran Wang; Jun Gou; Zhiming Wu; Jun Wang

doi:10.1038/s41377-020-00406-4

Light-modulated vertical heterojunction phototransistors with distinct logical photocurrents

Light Sci Appl. 2020 Sep 23:9:167. doi: 10.1038/s41377-020-00406-4. eCollection 2020.

Authors

Jiayue Han¹, Meiyu He¹, Ming Yang¹, Qi Han¹, Fang Wang², Fang Zhong², Mengjian Xu², Qing Li³, He Zhu³, Chongxin Shan⁴, Weida Hu^{2

3}, Xiaoqing Chen⁵, Xinran Wang⁵, Jun Gou^{1

6}, Zhiming Wu^{1

6}, Jun Wang^{1

6}

Affiliations

¹ School of Optoelectronic Science and Engineering, University of Electronic Science and Technology of China, Chengdu, 610054 China.
² State Key Laboratory of Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Science, 500 Yutian Road, Shanghai, 200083 China.
³ Hangzhou Institute for Advanced Study, University of Chinese Academy of Sciences, Hangzhou, 310024 China.
⁴ Henan Key Laboratory of Diamond Optoelectronic Materials and Devices, School of Physics and Engineering, Zhengzhou University, Zhengzhou, 450001 China.
⁵ National Laboratory of Solid State Microstructures, School of Electronic Science and Engineering, and Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093 China.
⁶ State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, 610054 China.

Abstract

The intriguing carrier dynamics in graphene heterojunctions have stimulated great interest in modulating the optoelectronic features to realize high-performance photodetectors. However, for most phototransistors, the photoresponse characteristics are modulated with an electrical gate or a static field. In this paper, we demonstrate a graphene/C₆₀/pentacene vertical phototransistor to tune both the photoresponse time and photocurrent based on light modulation. By exploiting the power-dependent multiple states of the photocurrent, remarkable logical photocurrent switching under infrared light modulation occurs in a thick C₆₀ layer (11 nm) device, which implies competition of the photogenerated carriers between graphene/C₆₀ and C₆₀/pentacene. Meanwhile, we observe a complete positive-negative alternating process under continuous 405 nm irradiation. Furthermore, infrared light modulation of a thin C₆₀ (5 nm) device results in a photoresponsivity improvement from 3425 A/W up to 7673 A/W, and we clearly probe the primary reason for the distinct modulation results between the 5 and 11 nm C₆₀ devices. In addition, the tuneable bandwidth of the infrared response from 10 to 3 × 10³ Hz under visible light modulation is explored. Such distinct types of optical modulation phenomena and logical photocurrent inversion characteristics pave the way for future tuneable logical photocurrent switching devices and high-performance phototransistors with vertical graphene heterojunction structures.

Keywords: Optical properties and devices; Optical sensors.